Not Applicable
The present invention relates to machines for excavating soils as necessary in construction projects. More specifically it relates to a machine that is adapted specifically for long narrow trenches and at the same time for more general excavations.
Long narrow trenches are required for installation of many utilities including water and sewer, gas, electrical power, and cable for communications. These utilities are often installed using machines known as trenchers, one example is illustrated in FIG. 1. A trencher 10 includes a trenching boom 40, with a boom frame 42 that supports an excavation chain 44 routed around and supported by end idler 46. The trenching boom 10 is mounted to a mobile chassis 12 capable of propelling the boom through the ground while the boom is lowered into the ground such that the end idler 46 is in a position to excavate to the desired depth. There are two basic types of chassis, a track chassis and a rubber tire chassis. FIG. 1 illustrates a rubber tire chassis, and that type of trencher is thus known as a rubber tire trencher.
Rubber tire trenchers have an advantage over track trenchers in that they are less disruptive to the ground. Thus, they are utilized in applications where maintaining the ground is important, such as when trenching through established yards. In this application the needed excavation varies widely. Thus, rubber tire trenchers typically include a variety of excavating attachments and can include a vibrating gearbox and mount for a plow on the rear of the machine beside the trenching boom, not shown, while including a backhoe 20 and blade 30 attached to the front of the rubber tire trencher 10.
While the rubber tire trencher offers great flexibility, its capability for general excavation with the backhoe 20 is somewhat limited by the chassis. The backhoe can be positioned around its pivot axis 22 while being controlled by an operator positioned in operator station 14. Any additional movement of the backhoe requires movement of the entire chassis.
Different machines have been developed for general excavation, and are generally known as Excavators, an example being a compact excavator 110 as illustrated in FIG. 2. The compact excavator 110 has evolved to include two basic parts, an undercarriage or chassis 112 and turret/turntable 116. The undercarriage 112 includes the chassis and typically tracks. It supports the turret/turntable 116 and typically also supports a backfill blade 130, which is positioned with cylinder 132.
The upper structure, turret or turntable 116 includes the power unit, typically a diesel engine and hydraulic system, the operator""s station 114, and a backhoe 120 mounted on a pivot 122. There is no limitation of the rotation of the turntable, it is able to rotate fully, mounted to the undercarriage 112 at the swivel joint, supported by a slew bearing. The swivel joint supports the turret 116 and further provides a valve to provide a flow path for oil to be transferred from the pump, a component of the power unit, to the track drive motors and cylinder that positions the backfill blade 130. This valve is constructed to allow the turret to rotate freely.
The operator""s station 114 is mounted on the turret 116, and the pivot for the backhoe 122 is positioned directly in front of the operator""s station. This arrangement provides good visibility of the backhoe 120, and provides for flexibility in applications. Examples of this flexibility are illustrated in FIG. 3 where the excavator 110 is shown digging near to an existing wall 2. In these illustrations it can be seen how the chassis 112 can be positioned near the wall 2, the turret 116 rotated such that the backhoe pivot 122 is adjacent the wall, and the backhoe 120 positioned parallel to the wall. As positioned, the bucket can scoop in a direction parallel to the wall to form trench 4. Once the bucket is full it can be lifted, and the backhoe 120 rotated in order to position the backhoe and bucket to a second position 120a, away from the wall, to drop the excavated material in a pile or into a truck.
Excavators have become a preferred arrangement for general excavation. However, when a job involves specifically forming a trench of a specific depth and width, this arrangement is not as productive as the trenching boom described earlier as a part of the rubber tire trencher, particularly when the trench is narrow.
FIG. 4 illustrates the use of a compact excavator 110, positioned in four different locations 110a, 110d, 110c, and 110d, as would be necessary to dig a trench. The compact excavator is operated in the first position 110a, while the backhoe 120 is utilized to dig a first section of the trench. After completion, the chassis is moved to a second position 110b, and the trench extended. This process is repeated 110c, and 110d until the trench is the desired length. This process requires a substantial amount of operator involvement.
By contrast, the rubber tire trencher is illustrated in FIG. 1 will require less operator involvement. This involvement includes first controlling the trenching boom 40 during a plunge-cut, as the boom is rotated clockwise to move the end idler 46 from a position above the ground, to a position where a trench of the desired depth is being formed. Subsequent operator control then involves adjusting the ground speed of the rubber tire trencher 10 to match the excavation capacity of the trenching boom 40.
Trenchers have not previously been installed onto compact excavators.
According to the present invention there is provided a modification to a compact excavator by adding an optional component, a chain trencher.
A broad object of the present invention is to provide an excavator with a trencher.
Another object of the present invention is to provide an excavator with a trencher in a way that will automatically prevent a backhoe portion of the excavator from coming in contact with the trencher.
Still another object of the invention is to employ such an excavator with a trencher in a way that will automatically prevent a backhoe portion of the excavator from coming in contact with the trencher, but also use a mounting structure for the backhoe which allows the backhoe to move around 360 degrees once the mounting structure and trencher is removed.
Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of the invention in conjunction with the accompanying drawings.